A device in which a pair of electrodes is made to face each other so that they have a nanogap in between and a nanoparticle or molecule is placed in the nanogap is regarded as promising as a new device because of its switching and memory functions. The inventor et al. aim to fabricate a single electron transistor (SET) by introducing a chemically synthesized gold nanoparticle into nanogap electrodes produced by electroless gold plating, and establish an SET integrated circuit that is activated at normal temperatures (Non-Patent Literature 1). The inventor et al. have also succeeded in producing nanogap electrodes having a gap length of 5 nm or shorter at the yield of 90% (Non-patent Literature 2), and furthermore, developed “molecular ruler electroless gold plating: MoRELGP” process using a surfactant molecule as a template, and established a technology to produce nanogap electrodes having a gap length of 2 nm with a high degree of reproducibility (Patent Literature 1 and Non-Patent Literature 3).
Meanwhile, Non-Patent Literature 4 describes the operation of a single-electron memory in a transistor having a structure where a poly Si ultrathin film thin wire and a gate electrode cross each other via an oxidized film. The poly Si has a structure where crystalline particles of a sire of several nm are placed closely to one another, and when gate voltage is applied poly Si crystalline particles are filled with electrons, and a percolation path is established, allowing current to flow between a source and a drain. Furthermore, when a high voltage is applied as a gate voltage, electrons are captured into accumulated dots, and due to Coulomb repulsion among electrons, conductance of the current path changes, generating memory effect.
Non-Patent Literature 5 discloses a technology to cover a carbon nanotube with a SiN film, provide an Au dot and a blocking layer Al2O3, use the Au dot as a charge accumulation node, and provide a top gate on the node.